Signaling system



HANSCOM SIGNALING SYSTEM Filed March 23, 1,939

Avon/v5 Patented Dec. 10, 1940 I UNITED STATES STGNALING SYSTEM`Clarence D. Hanscom, Denville, N. J., assignor to Bell TelephoneLaboratories, Incorporated, New York, N. Y., a corporation of New YorkApplication March 23, 1939, Serial N0. 263,585

Claims.

This invention relates to telephone systems and particularly toimprovements in automatic telephone systems.

An object of the invention is to simplify anc.

5 improve automatic telephone systems of the character in whichconnections are established over a path including the beam of anelectronic device.

Heretofore systems have been provided in l0 which a connection from onesubscribers line to any one of a plurality of other subscribers lineshas been established by deilecting the beam in a cathode ray tube tocorresponding contacts at the end of the tube and using the beam as partof the talking path. I

The present invention has been applied to an arrangement of this kind inwhich a cathode ray tube is employed as the selector for establishingtelephone connections by the deection of an electronic beam by dialpulses; and a feature thereof is thev arrangement whereby the beam ismaintained locked in a deected position by a circuit over the beam andwhereby the dial pulses causing the deection are extinguished as soon asthe deflection is accomplished.

The invention has been illustrated in the accompanying drawing whichshows a calling subscribers line and a cathode ray tube used as theselector employed in accordance with the principles of this invention.

Referring now to the drawing a subscribers substation has been shown atl with the line terminating in the cathode ray tube 2 which is providedwith the usual filament 3 connected to a suitable source of current forthe production of an electron beam through the tube. This beam isemployed as the selecting means and as a path for talking current aswill hereinafter` be described. The cathode element i is connected tothe subscribers line, and an anode 5 is provided to control andconcentrate the beam of electrons as is Well known in the art. Thebattery 24 is provided to impress a positive potential on anode 5 withrespect to cathode A pair of deflection plates 6 and 'l are provided inthe tube in any well-known manner to deflect the beam onto the anodeterminals shown located at the end of the tube and collectively markedwith the numeral 8. To these terminals are connected individualconductors. The rst conductor 9 represents one conductor of the :firstsubscribers line and the remaining conductors lead to other equipmentsof this kind for other subscribers lines and are equally spaced withrespect to each other, except the distance between the conductor 9 andthe second conductor I0. This distance represents, if the subscriber atl is considered as the rst subscriber in a group of ten, two spaces sothat when the beam is deiiected to select the second subscriber it mustbe deflected two steps. The 5 rst step will point the beam onto aterminal ll which is provided for holding the beam between pulses aswill hereinafter be described. The corresponding terminals for thesecond subscriber terminate in the group designated with the refl0erence character l2 and the corresponding terminals for a thirdsubscribergterminate in the group designated with the number I3. Anotherconductor I4 is common to all groups of conductors leading to all of thesubscribers equipi5 ments.

The individual subscribers conductors as for example, the group 8terminating at the first subscribers equipment are connected toindividual filters marked as'a group with the numeral l5 20 and providedto prevent voice currents from passing through the resistances I6 to theconductor Il which is employed as will hereinafter be described inconnection with the operations of the circuits.

Two discharge tubes i8 and i9 are connected through various circuitsincluding sources of potentials and an induction coil 2li, one windingof which is connected to a dial 2| for the sending of the impulses todeilect the beam to the proper 30 terminal in the tube 2. The tube l@may be of the gas-filled type, so that the anode discharge currentcontinues to flow following the removal of the input signal.

A detailed description will now be made of the 35 operationof thissystem in the selecting and establishing of a connection from thesubscriber at l to one of the other nine of the group of tensubscribers. It should be noted that normally the electrons emitted fromthe cathode l provide a 4@ cathode ray beam 22 which is controlled bythe anode 5 and normally maintained deflected by the potential diierencebetween plates 6 and 'l to strike the terminal 23 so that calls incomingto subscriber I may pass over this beam as will here- 45 inafter bedescribed. With this in mind. if the subscriber at l removes hisreceiver from its switchhook, he closes the circuit between the elementd and the anode 5 through the battery 2t to control the beam toestablish a talking con- 5o nection as will be described. If thesubscriber then operates his dial 2l by closing a connection between thepulse contacts, it will be noted that on therst impulse the potential onthe grid 25 of the tube I8 will be changed to become less 55 ment 33,plate 34, resistance 35, back to battery 32. It will be observed that itis the connection through the potentiometer 39, the battery 31, and

resistance 35 that normally maintains a potential difference between theplates 9 and 1 to maintain the beam 22' on terminal 23. On the otherhand on the establishing of the circuit through the output circuit oftube I8, the potential between plates 6 and 1 is changed so that thepotential on plate 6 becomes less positive in relation to thepotential-on plate 1. This change is sufficient to deflect the beam fromthe terminal 23 one step downwardly to strike the terminal I I. Noselective connection will be established across the beam at" this timeas it takes two impulses to establish a connection to terrnlnal 39 forestablishlng a connection to the second subscriber in the group of ten.

It should be explained at this point how the beam is maintained on aterminal after having been once set. The operations in this respect areas follows: A current through the output circuit of tube I9 also owsthrough the primary winding 40 of theinduction coil 4I. This causes amomentary impulse of current to ow through the secondary winding 42 ofthis induction coil 4I which has the eect of making the grid 43 lessnegative in relation to the potential of filament 44 as normallyestablished by the battery 45 and potentiometer t6 in parallel and theconnection through the secondary winding 42 of the induction coil 4Ibetween the filament 44 and the grid 43. This momentary change ofpotential between these elements causes a current to flow through theoutput circuit of the tube for maintaining the potential difference nowestablished between the plates 6 and 1 as follows: From filament 44,

battery 50, conductor I1, resistances I6. second terminal Il, beam 22,element 4, contacts on the switchhook of subscriber I, primary winding52 of induction coil 20, resistance 35, battery 54, plate 55, back tofilament 44. As the plates 6 and 1 are connected to opposite sides ofresistance 35, the potential difference established between these plateswill now be maintained iby this circuit through resistances I6 so thatthe beam will be held on the terminal Il. this circuit also establishesthrough the circuit including Winding 21 of the inductance coil 20, amementary impulse which is in opposition to the current passed throughthis circuit by the clos-- ing of the contacts at dial 2i and thereforeextinguishes the pulse established by their contacts at 2I through theoutput circuit of tube I8. Thus the impulse that causes the beam to stopis quenched immediately to obviate the possibility of moving the beam asecond step accidentally.

'The circuits now remain in this condition so' that beam 22 is held onterminal II until the next impulse comes along.

When this takes place,`that is, when the contacts of dial 2| are againclosed, the potential difference between the plates 6 and 1 is againchanged, and thus causes the beam to be deilected to strike terminal 39whereupon the abovementioned circuit through the tube I9 and re;-sistances I6 is closed with the exception that a portion of thisresistance is eliminated so that the beam will now be maintained on thisterminal until the next impulse comes along. The

The current through 2,224,677 negative due to the connection of thebattery 26 second impulse is extinguished by the momentary impulsethrough the winding 21. These operations are then repeated if additionalimpulses are sent and the potential on plate 8 is made less and lesspositive as the' resistance through the circuit for maintaining thepotentials decreases as additional units of the group I6 are eliminated.i

The line potential filters shown at I5 are as stated for the purpose ofpreventing talking current from disturbing the holding circuits. Thereis one of these filters inserted in each line between the resistances I6and the terminals associated therewith.

If it is assumed that only two impulses are sent, the beam will remain'on terminal 39 and a connection will therefore be established over thecommon conductor I4, the subscribers telephone set I, control element 4,beam 22, terminal 39 and the conductor I0, thus causing the selection ofthe second subscriber. This circuit is continued over the conductor I0through talking battery 51. The conductor vI9 terminates in the secondsubscribers cathode ray tube at the rst terminal corresponding to`terminal 23 in tube 2. From there it is extended through the beamcorresponding to beam 22, the element corresponding to element 4,through the called subscribers ringer back over the common conductor I4.This causes the called subscribers ringer to operate and when the calledsubscriber answers, the ringer is eliminated and a connection iscompleted for talking between the first and second subscribers. If thesecond subscriber had called the first subscriber, he would have dialedone impulse and established a connection through his tube, overconductor 9, through talking battery 60, beam 22, element 4, subscribersringer at station I, common conductor I4, back to the second sub-lscribers equipment, over the elements and beam of the tube correspondingto tube 2 to conductor 9. In a similar manner connections may beestablished from any subscriber to any` other in the system disclosed inthis drawing which comprises as stated a group of ten subscribers lines.

What is claimed is:

1. In a signaling system, a cathode ray tube, a 'plurality of anodes insaid tube, means for deflecting the cathode ray in said tube from oneanode to another, and means operative over said ray for maintaining theray deflected on an anode after having been deflected by said rst meansto said anode and until said first means again deflects the ray to asucceeding anode'.

2. In a signaling system, a cathode ray tube, signaling circuits, aplurality of anodes in said tube, means for transmitting momentarilysucceeding impulses, means for deilecting the cathode ray in response tosucceeding impulses from one anodelto another to select said signalingcircuits, and means for maintaining the ray deected on an anode betweenimpulses.

3. In a signaling system, a cathode ray tube, a plurality of anodes insaid tube, an impulse transmitter, means for deilecting the cathode rayin said tube from one anode to another in response to succeedingimpulses from said transmitter, and means for maintaining the deflectedray in the deflected position on an anode after the impulse havingdeflected it`to said anode ceases and until the ray is again deected byansaid tube from one anode to another in response to succeeding impulsesfrom said transmitter, means for operating said deecting means tomaintain said ray deflected between impulses and forextinguishing saidimpulses as soon as they have deflected the ray.

5. In a signaling system, a cathode ray tube, a plurality of anodes insaid tube, an impulse transmitter, means for deilecting the cathode rayin said tube from one anode to another in response to succeedingimpulses from said transmitter, and circuit means including the ray foroperating said deecting means to maintain said ray deiiected and forextinguishing said impulses as soon as they have deected theray.

6. In a signaling system, a cathode ray tube, a plurality of anodes insaidtube,-. means for deiiecting the cathode ray in said tube from oneanode to another, a circuit closed over said ray when deected to ananode for-maintaining said ray deected on said anode until again deectedto another anode, and -a communication circuit established over saidcathode ray.

7. 'I'he combination in signaling system of an electron discharge tubehaving a plurality of electrodes and means for producing an electrondischarge, a plurality of telephone lines connected respectively .tosaid electrodes, means for progressively deecting the electron dischargefrom one electrode to the next to select a desired one of said telephonelines, circuit means including the electron discharge for maintainingsaid discharge on each successive electrode to which it is deflected,and circuitmeans including said electron discharge -for establishing atalking connection with the selectedone of said telephone lines. 8. In asignaling system, a cathode ray tube. a plurality of anodes in saidtube, animpulse transmitter, means for deecting the cathode ray in saidtube from one anode toanother in re-l sponse to succeeding impulses fromsaid transmitter, a discharge tube, means for actuating said dischargetube in response to succeeding impulses from said transmitter, and meansresponsive to the actuation of said discharge tube and includingsaidcathode ray for extinguishing said impulses as soon as they have deectedthe ray and for operating said deecting means to maintain said raydeilected on the anode to which it has been deiiected by a precedingimpulse until a succeeding impulse is received.

9. In a cathode ray tube, deflection plates in said tube, a plurality ofanodes in said tube, an impulse transmitter, a discharge tube, a circuitbetween said impulse transmitter and said discharge tube for theactuation of the discharge tube in response to impulses from saidtransmitter, an output circuit'from said discharge tube to said deectionplates for, deecting the cathode ray from one anode to another insuccession in response to impulses from said transmitter, a seconddischarge tube, an input circuit for said second discharge tubeassociated with the output circuit of said ilrst discharge tube foractuating said second dischargetube each time said output circuit isactuated, an output circuit for said second discharge tube including thecathode ray for maintaining tre deection of the ray as deflected by apreceding impulse and for quenching said preceding impulse as soon assaid output circuit of said second discharge tube becomes effectiveuntil a succeeding impulse is received to deflect the ray to asucceeding anode.

10. In a signaling system, a cathode ray tube having ldeflection plates,a calling signaling circuit associated with said tube, a plurality ofanodes in said tube, a signaling circuit associated with each anode, animpulse transmitter,

means including a' discharge tube and the deflection plates operative inresponse to succeeding impulses from said transmitter .to deiiect thecathode ray from one anode to another to select a signaling circuit andconnect it to the calling signaling circuit over said ray, a seconddischarge tube associated with said rst discharge tube and

